Impact Of Wind Power Grid Connection On Power System Stability And Control Strategy

At present,a grid-independent power adjustment method is adopted in variable-speed wind turbines in order to obtain the maximum energy utilization rate,which leads to the decoupling of the wind turbine speed from the grid frequency.The main research contents of this article are listed as follow:Firstly,the working principle of the converter control system of wind turbine based on the stator voltage directional control strategy is analyzed.On this basis,the rotor side power outer loop additional stator side vector control scheme is proposed to achieve decoupling control.The mathematical model of wind power grid connected system is established,and the wind turbine is equivalent to variable ground admittance.The influence mechanism of wind turbine incorporation on the self admittance of conventional generator is studied.Secondly,a small signal model of the wind power grid-connected system is established,and the influence of wind power active power control parameter settings on the damping ratio of the system is analyzed.It is concluded that the additional active power control attached to wind turbines may have a negative damping effect on the system oscillation.Then,combined with the analysis of the influence mechanism of the additional power control on the transient stability and small disturbance stability,combined with the influence characteristics of the power angle and the wind turbine shafting,a comprehensive control strategy of the phased variable coefficient additional power is proposed,and the implementation method is proposed.Finally,based on the Matlab/Simulink simulation platform,an interconnected grid model with high-permeability wind power is built.Different power control methods are set for the wind turbines connected to the system,and the system is simulated to obtain the synchronous generator and wind power's response.The simulation results show that during the transient event,the high-permeability wind power grid-connected system has flexible power response capabilities,the ability of frequency adjustment is enhanced effectively,and the transient stability performance of the system is also improved.